Profen-types of compounds are typically defined as propionic acids (or esters) bearing at least one aromatic substituent, usually .alpha.- to the carboxylic function.
These carboxylic acids have an asymmetric carbon atom (the carbon atom adjacent to the carbonyl group) that typically produces a racemic mixture of these acids [a mixture of both of the (+) and (-) or dextro and levo rotorary forms]. For example, ibuprofen [(2-(4-isobutylphenyl)propionic acid)], a commercially and pharmaceutically important chemical compound, is typically produced and sold as the racemic mixture. Many other of the pharmaceutically-active profen drugs are also produced as racemates and administered in this form. However, it is well known that the physiological utility of the racemic mixtures is almost exclusively focused on one enantiomer, the other having either no effect or even diminishing the effect of the active enantiomer. Thus the S(+) form of ibuprofen is physiologically active in reducing inflammation and in providing an analgesic effect. See, for example, U.S. Pat. Nos. 4,851,444 and 4,877,620. The R(-) enantiomer is devoid of activity for these indications, although it is, in part, converted in vivo into the S(+) compound. Other profens, i.e., naproxen, are only prescribed as the single enantiomer.